Luminescence measurements of chromate ions(CrO42−)adsorbed onto disperse silica(SiO2)surfaces under intense pulsed ultraviolet excitation (&lgr;exc=354.7or 266 nm,&tgr;p=20 ns) were performed at room temperature. The luminescence spectra were collected for different values of the excitation intensity (I). The luminescence yield in the red band corresponding to emission fromCrO42−ions varies linearly withIunder 354.7 nm excitation. However, the intensity dependence of the luminescence yield under 266 nm excitation is characterized by a threshold(I∼0.6×106 W cm−2),after which the intensity dependence of the luminescence yield is described by a power law with indexn=1.7and then saturated atI∼1.0×106 W cm−2.This feature of the excitation dynamics has been attributed to stimulated emission and considered by means of a four-level scheme. The cross section of stimulated emission was estimated as∼3.3×10−21 cm2.©1997 American Institute of Physics.